# IMAGE PROCESSING

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" Two roads diverged in a wood, and I,
I took the one less traveled by,
And that has made all the difference "-Robert Frost

### Convert HSI Image to RGB Image

CONVERT HSI IMAGE TO RGB IMAGE:

Refer How to convert the RGB image to HSI Image

MATLAB CODE:

`````` figure,imshow(HSI);title('HSI Image');
%Obtain the Hue, Saturation and Intensity components
H1=HSI(:,:,1);
S1=HSI(:,:,2);
I1=HSI(:,:,3);

``````

`````` %Multiply Hue by 360 to represent in the range [0 360]
H1=H1*360;

%Preallocate the R,G and B components
R1=zeros(size(H1));
G1=zeros(size(H1));
B1=zeros(size(H1));
RGB1=zeros([size(H1),3]);

%RG Sector(0<=H<120)
%When H is in the above sector, the RGB components equations are

B1(H1<120)=I1(H1<120).*(1-S1(H1<120));
R1(H1<120)=I1(H1<120).*(1+((S1(H1<120).*cosd(H1(H1<120)))./cosd(60-H1(H1<120))));
G1(H1<120)=3.*I1(H1<120)-(R1(H1<120)+B1(H1<120));

%GB Sector(120<=H<240)
%When H is in the above sector, the RGB components equations are

%Subtract 120 from Hue
H2=H1-120;

R1(H1>=120&H1<240)=I1(H1>=120&H1<240).*(1-S1(H1>=120&H1<240));
G1(H1>=120&H1<240)=I1(H1>=120&H1<240).*(1+((S1(H1>=120&H1<240).*cosd(H2(H1>=120&H1<240)))./cosd(60-H2(H1>=120&H1<240))));
B1(H1>=120&H1<240)=3.*I1(H1>=120&H1<240)-(R1(H1>=120&H1<240)+G1(H1>=120&H1<240));

%BR Sector(240<=H<=360)
%When H is in the above sector, the RGB components equations are

%Subtract 240 from Hue
H2=H1-240;

G1(H1>=240&H1<=360)=I1(H1>=240&H1<=360).*(1-S1(H1>=240&H1<=360));
B1(H1>=240&H1<=360)=I1(H1>=240&H1<=360).*(1+((S1(H1>=240&H1<=360).*cosd(H2(H1>=240&H1<=360)))./cosd(60-H2(H1>=240&H1<=360))));
R1(H1>=240&H1<=360)=3.*I1(H1>=240&H1<=360)-(G1(H1>=240&H1<=360)+B1(H1>=240&H1<=360));

%Form RGB Image
RGB1(:,:,1)=R1;
RGB1(:,:,2)=G1;
RGB1(:,:,3)=B1;

%Represent the image in the range [0 255]
RGB1=im2uint8(RGB1);
figure,imshow(RGB1);title('RGB Image');

``````

Explanation

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praveena puppy said...

Hey, nice site you have here! Keep up the excellent work!

Image Processing

Good job!

durre shehwar said...

Really helpful blog..Keep it up... (Y)

It gives me following error.
Undefined function 'cosd' for input arguments of
type 'uint8'.

Error in hsi2rgb2 (line 29)
R1(H1<120)=I1(H1<120).*(1+((S1(H1<120).*cosd(H1(H1<120)))./cosd(60-H1(H1<120))));
can yo please help me with this i m just a beginner

Aaron Angel said...